abc's david wright is in big bear lake. >> suspect vehicle still outstanding. it's a black nissan titan. >> reporter: police officers hunting one of their own. a rogue former officer, now accused of hunting them. >> of course, he knows what he's doing. we trained him. he was also a member of the armed forces. it's extremely worrisome and scary. >> reporter: it started sunday with a double-homicide. monica quan and her fiance, keith lawrence, shot in their car. a murder with no apparent motive. >> we've identified christopher jordan dorner as a suspect in this double-homicide. >> reporter: 33-year-old gister if dorner, a lieutenant in the navy reserves, honorably discharged last friday. fired four years ago by the lapd. police claim he bore a grudge against an lapd police captain, randy quan, monica's father, as well as other lapd officers. >> a particular interest is a multipage manifesto. >> reporter: a rambling manifesto posted online, dorner blames quan and other lapd officers of a smear campaign, after dorner reported witnessing a fellow officer commit poli